“Listen, he’s got a book to sell . . .”

Douglas Alexander, a self-proclaimed "optimist by nature", is in good spirits. Fresh from Tuesday's three-hour strategic political cabinet meeting, which followed a gathering of the Parliamentary Labour Party (PLP) the previous night, Alexander is confident that Labour is now united and ready for the challenges ahead.

The Labour campaign co-ordinator and International Development Secretary has been the subject of speculation in recent weeks, including over his role in the coming election. This followed rumours last year that this loyal ally to the Prime Minister - who started his political career as Gordon Brown's researcher in 1990 - had been "sidelined", culminating in a sombre interview with the New Statesman in July in which he accepted that some Brown aides had briefed against him.

Whatever the truth of past claims, Alexander is now firmly back in the loop. This was demonstrated to MPs by his address to the PLP. (As he sat down between Peter Mandelson and Brown, it struck him that the three had first worked together 20 years ago.) And it was demonstrated to the cabinet when he opened the week's session with a presentation on campaign strategy.

Post-coup consensus

Taking a soft seat in the corner of his spacious departmental office in Palace Street, Alexander talks about that strategy and sets the record straight. It is his first interview since newspaper revelations appeared to place him firmly at odds with the Prime Minister, more of which later. "I've come back from the political cabinet buoyed by not just the quality of the discussion," he says, "but the depth of consensus about how we're going to fight this election."

So what was the mood of the PLP following the abortive "coup" on 6 January, led by the former cabinet ministers Geoff Hoon and Patricia Hewitt, who were asking for a secret ballot on Brown's leadership? "I could show you the text messages I received afterwards: there was similarly a sense of unity and common purpose."

Yet Alexander is also frank about the effect of such "coup" attempts. "Listen, it hasn't helped. But my sense and my understanding from the polls that we've seen since then is that it came and went . . . It is already behind us."

He denies that Brown is now "boxed in". On the contrary: "However inadvertently, the consequence . . . is certainty that Gordon will lead us into the next election . . . and that is the foundation on which we can work together as a team, because our generation - our younger generation than Peter Mandelson and Gordon - is not ready to hand over this country to a party that we think has the wrong solutions for the people we came into politics to serve."

But what of claims - including one by the political editor of the BBC - that Alexander himself was among a handful of cabinet ministers ready to resign amid a coup if the circumstances were right? "There are always rumours in politics and I'm responsible for many things, but not some of the headlines that are written or some of the words that are spoken. I've supported Gordon in the past, I offered a statement of support on the day and I will support him as he leads us into the general election. I don't know how I can state it more clearly than that."

He corrects reports that he capitalised on the putsch by gaining concessions from Brown. “I didn't actually have a meeting with him on Wednesday afternoon, but I've never shied away from speaking to Gordon. That may have upset people around him in the past, but after 20 years we're still talking."

Indeed, Alexander points out that he spoke to Brown again after the PLP . What's more: "I spoke more to the Prime Minister on Sunday [10 January] than to my wife and kids, as they pointed out repeatedly!"

It was on that day that the Mail on Sunday serialised Inside Out by former Labour Party general secretary Peter Watt. In the book, Watt attributes the following words to Alexander at the time of the 2007 election-that-wasn't: "The truth is, Peter, we have spent ten years working with this guy [Brown], and we don't actually like him. We have always thought the longer the British public had to get to know him, the less they would like him as well."

Alexander says his words were "paraphrased" and adds: "Listen, I have said that was not my view. It seems that Peter Watt himself does not seem certain what he claims I said. I would just ask you to weigh 20 years of working with Gordon against 20 words that were apparently paraphrased. But listen, he's got a book to sell. There are bigger and more important issues that we are focused on."

All the while, Alexander is relaxed about speculation over who's up and who's down when it comes to the election team. "My sense is that titles matter less than team. I was thinking about this after the PLP: I honestly can't remember what Peter Mandelson's title, Gordon Brown's title, Philip Gould's title, or anybody else's title was in 1997, or indeed in most elections since then.

“What matters in any campaign is that you have a strategic core that makes the judgements, decides the strategy, and can deliver."

“Cartoon characters"

Alexander is in no doubt about the scale of the challenge facing Labour as it seeks a fourth term. "Look, we have a tough fight on our hands. The poll averages are the Conservatives on around 40, and we're on about 30. We've made some progress in closing that gap in the autumn, but we've got a lot of work to do and not a lot of time in which to do it. And it was with a clear-eyed sense of obligation to the people we came into politics to serve that we engaged in the conversation."

He dismisses talk of disagreements in cabinet over "dividing lines", characterised as being between Mandelson and Ed Balls. "I don't recognise the characters, either from the internal conversations of which I've been part, or from the cartoon characters that have been running around the newspapers." But he does subtly make the case for an unashamedly social-democratic message.

“I do think our challenge is to balance credibility, and a clear message about how we would reduce the deficit, with boldness about the choices that we put before the public. It would be wrong for us to offer difference from the Conservative Party at the cost of credibility, but equally, it would be wrong to offer credibility at the cost of being clear that there remain very fundamental differences. I think there is a broad consensus on that issue."

Alexander is keen to learn lessons from Barack Obama's US presidential election victory in 2008. "We've been looking quite carefully at the Obama campaign, and talking to some of the senior Obama strategists," he says. "He is a superb communicator in a huge rally, but they made a very conscious decision that he was also going to be meeting and talking with the voters as well, and in that sense we need to think in terms of how we engage with the public in this campaign. There is work under way on that . . .

“Look at the Conservatives: they're running a broadcast campaign in a networked world. If you look at their poster advertising - a thousand posters last week - I think the idea that you have one-way dialogue with the public . . . fails to recognise the appetite for engagement."

Alexander claims to be masterminding an entirely new type of campaigning. "The other point that I touched on at cabinet is that we need this to be a different kind of campaign because I think there is a public appetite for a different kind of campaign. My sense is that people feel that politics as usual is broken, and we need to reflect that appetite for change in both what we offer and how we campaign. I think the wrong place for us to be, would be for the Conservative Party to be saying, 'We're for change,' and Labour to be saying, 'We're for the status quo, for experience.' We need to prove that this election is going to have two competing offers on change: the right change with Labour and the wrong change with the Conservatives."

The election co-ordinator also admits to a sense that Labour has only now moved into campaign mode. "We've done a lot of thinking on these issues and there is a moment where you move from governing to campaigning. I think it's fair to recognise that there has been a delay in that explicit transition, but that was not by inadvertence, but by conscious choice. We made a decision in the late summer/early autumn [2009] - reflected in our slogan 'Securing Britain's Future' - that the right thing for the country was to focus, laser-like, on securing the recovery. But we were also conscious that if we got the policy right it would be the best platform for us to get the politics right."

Unlike some Labour MPs, Alexander, who joined Labour in 1982, is a street fighter with as much experience of the bad times as the good. He repeats a message he gave the PLP: "My formative experience was not of success, in 1997; my first experience of campaigning was one of repeated and bitter disappointment - in 1983 and 1987 and then in 1992. And I made a resolution at that point, along with many others, that we would never again be out-campaigned by a party that could have a better campaign but poorer values.

“I think we have the policies, I think we have the people, I think we have the values. Our task is to commit with determination to pull back the opinion polls and offer to the British people the choice that they want."